Shapes with SVG and CSS
This example shows how to build a simple emoji-like face using SVG shapes and CSS. It displays a yellow circle with two black eye circles and a curved mouth path, all positioned within an SVG canvas. The code demonstrates basic D3.js selection and append methods, using `d3.select`, `d3.arc`, and attribute chaining to create and style the shapes. The mouth is generated with the D3 arc generator, which computes a path based on specified inner and outer radii and angle values. A single CSS file handles page margins and overflow settings.